Printing press feeder

ABSTRACT

A mechanism for feeding lightweight sheets of paper, one at a time, to a printing press in which a rotationally oscillated vacuum drum with suction holes therein grasps pieces of paper off the bottom of a stack with each oscillation. The stack is adjustably supported at a predetermined height just above the oscillating feed drum to insure that only one piece of paper at a time is selected. An air jet is used to separate the edges of the paper sheets in the stack while a separating plate next to the drum operates to block off the suction holes at the end of each oscillation and separate each piece of paper from the oscillating drum.

United States Patent Paulson [151 3,655,181 [451 Apr.11,1972

[54] PRINTING PRESS FEEDER [21] Appl. No.: 100,851

Pn'mary Examiner-Joseph Wegbreit Anomey-Robert M. Dunning [57] ABSTRACTA mechanism for feeding lightweight sheets of paper, one at a time, to aprinting press in which a rotationally oscillated vacuum drum withsuction holes therein grasps pieces of paper off the bottom of a stackwith each oscillation. The stack is adjustably supported at apredetermined height just above the oscillating feed drum to insure thatonly one piece of paper at a time is selected. An air jet is used toseparate the edges of the paper sheets in the stack while a separatingplate next to the drum operates to block off the suction holes at theend of each oscillation and separate each piece of paper from theoscillating drum.

AIR SOURCE Patented April 11, 1972 3,655,181

2 Sheets-Sheet 1 AIR INVENTOR v ow E PAULSO/V BY g ATTORNE Patehted Aril 11, 1972 2 Sheets-Sheet 2 INVENTOR HAROLD R PAUL 50/V n ATTORNEY 1PRINTING rnnss FEEDER BACKGROUND OF THE INVENTION In the prior art, manytypes of printing press feeders have been used but all of them haveinherent difficulties which makes them less than suitable. In an attemptto overcome these difficulties I have invented an oscillating drumprinting press feeder which selects pieces of stock from the bottom of astack. This invention is the subject of my co-pending patent applicationfor Printing Press Feeders, Ser. No. 68,819 filed on Sept. 2, I970. Theprinting press feeder of the above referenced co-pending applicationcomprises a compact long lasting feeding mechanism which is readilyadjustable to many different sizes of stock without any changes in thebasic pickup mechanism. However, a need has arisen for a feedingmechanism of this sort which can handle extremely thin lightweight paperwhich until the advent of my invention has posed a particular problemdue to the fact that it is difficult to separate one thin piece of paperfrom another without damaging them.

SUMMARY OF THE INVENTION Briefly, the present invention operates to feeda stack of paper or other suitable stock by means of a guide rack ontothe top surface of an oscillating cylindrical feed drum. The drum ishollow and connected to a vacuum source which sucks the stock intocontact with the oscillating drum through small holes in the surface ofthe drum. As the drum rotates away from the stack it pulls the bottompiece of paper with it and feeds that piece between a pair of transferrollers. The rollers direct this paper into the printing press. As theoscillating vacuum feed drum rotates back underneath the stack of paperit grasps the next piece and repeats the cycle. In order to handle verylightweight paper a number of unique improvements have been incorporatedinto this feeder.

The cylindrical portion of the feed drum is provided with a plurality ofgenerally rectangular circumferential grooves. As the drum rotates itpasses underneath a separation plate which separation plate has a numberof generally rectangular teeth extending from its edge into thecircumferential grooves. As the drum rotates, the vacuum holes passunderneath the separation plate thus cutting off the suction force onthe paper. Simultaneously, the projections on the separation plategently lift the paper away from the feed drum and direct it into thetransfer rollers. In order to insure that only one piece of paper isselected at a time by the feed drum the stack of paper is supported on arack which is very accurately adjustable in height so that the edges ofthe bottom of the stack are positioned at an exact predetermineddistance above the feed drum. In addition, a jet of air is directed atthe edges of the bottom pieces of paper so as to separate them andinsure individual selection. It may therefore be seen that it is anobject of the present invention to provide an improved printing pressfeeding means. It is another object of the present invention to providea feeding means which can handle extremely lightweight sheets of paper.Other objects and advantages will become apparent upon consideration ofthe following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side view of theprimary components of my invention demonstrating how each piece of paperis selected and fed into the printing press.

FIG. 2 is a schematic top view of most of the same primary componentsshown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring simultaneously to bothFIG. 1 and FIG. 2, a pair of frame members and 12 are shown which carrya shaft 14 therebetween. Connected to shaft 14 is the oscillating feeddrum indicated generally by the numeral 25. Feed drum 25 is groovedcylindrical portion 26. These two portions are connected together bysuitable bolts such as bolts 28 and 29. Shaft 14 is connected by meansof a crank 15 to a push rod 17 which in turn is connected to anoscillating drive 19. This connection is shown only in FIG. 2 by meansof a dashed line 21. Also disposed for rotation on shaft 14 are a pairof transfer rollers 16 and 18 upon which rotate another pair of transferrollers 30 and 32. Rollers 30 and 32 are supported for rotation about ashaft 34. Shaft 34 is cut away in two places in FIG. 2 so as to betterexpose the components underneath. Transfer rollers 16, 18, 30 and 32 areall powered by means not shown in the present drawings. Reference shouldbe had to the above referenced co-pending application for similarapparatus and a more detailed explanation of its operation.

In order to handle lightweight pieces of paper the present inventioncontemplates a number of substantial design improvements as can be seenmost readily in FIG. 2. In FIG. 2 it can be seen that cylindricalportion 26 of feed drum 25 is provided with four generally rectangulargrooves numbered 40 through 43. Disposed between grooves 40 through 43are three suction holes 45 which connect with the interior of feed drum25. The interior of feed drum 25 is further connected through shaft 14and a flexible hose 50 to vacuum pump 52. These connections are similarto those disclosed in my copending patent application mentioned earlier.By means of this connection to vacuum pump 52 a desired suction ismaintained through holes 45 in the grooved cylindrical portion of feeddrum 25. Immediately adjacent to feed drum 25 is a separating plate 54which has four projections 56 thereon which extend snugly into grooves40 through 43. Plate 54 is cut away for clarity so only two projections56 are visible in FIG. 2. As feed drum 25 is oscillated back and forthby oscillating drive 19 the vacuum holes periodically pick up a piece ofpaper and carry it over onto the top of the projections 56 and thenceonto the top of separator plate 54. Simultaneously, as this happens,holes 45 pass underneath separator plate 54 so that the suction force iscut off preventing any damage to the lightweight pieces of paper. As thepaper passes on to separator plate 54 and the suction from holes 45 iscut off the leading edge of the paper is fed between transfer rollers 18and 16 and transfer rollers 30 and 32 which maintain the motion of thepaper to the right in FIG. 2 across the top of separator plate 54 andalso across a pair of plates 60. and 62. This motion to the right isadditionally encouraged by a pair of rollers 20 and 22 which are formedas extensions from the end of transfer rollers 16 and 18 respectively.It should be noted that transfer rollers 30 and 32 slide on rod 34 andin operation are usually positioned to ride on rollers 20 and 22.

The stack of paper is supported just above feed drum 25 by an adjustableplate 70 which is cut away in FIG. 2. To better understand how plate 70carries the stack, reference should be had to FIG. 1. In FIG. 1 it canbe seen that stack supporting plate 70 is pivoted at its rear edge abouta pair of pivot pins 72 and 74 which pins extend out from a frame member76. A stack of paper 78 is supported on stack supporting plate 70 withthe edges of the paper extending slightly over and just above feed drum25. A pair of thumb screws 80 and 82 are located on each side of themachine threaded through a pair of mounting blocks 84 and 86. Thesethumb screws bear against the underside of support plate 70 and permit aprecise adjustment of the height thereof. By turning thumb screws 80 and82 one can be sure that the bottom of the stack of paper 78 is exactlythe right distance above feed drum 25 so that one piece of paper at atime is selected by the grasping force of the suction holes 45. Eachselected piece of paper must pass between feed drum 25 and a verticalseparator bar which extends almost down to the top of feed drum 25.Vertical spearator bar 90 is supported by a bracket 92 mounted on across bar 94 extending between the two frame members 10 and 12 of theprinting press. Vertical separator bar 90 and its supports are not shownin FIG. 2 for clarity. In FIG. 1 it may additionally be seen that an airsource 95 is connected by means of any suitaforrned in two halves, one abracket portion 24 and the other a 75 ble conduit 96 to verticalseparator bar 90. A hollow passage way 97 down the center of verticalseparator bar 90 serves to direct the flow of air from air source 95 toa nozzle 98 positioned at the bottom of vertical separator bar 90.Nozzle 98 directs a jet 'of air toward the bottom of stack 78. This jetof air serves to separate the various pieces of paper so as to furtherinsure that only the bottom most piece of paper is selected with eachoscillation of feed drum 25. It should also be noticed in FIG. 1 thatthe bottom of the projections 56 from separator plate 54 are beveled tomatch the bottom of the grooves 40 through 43 in the cylindrical groovedportion of the feed drum 25. A pair of stack indexing bars 99 and 100are fastened to frame members and 12 in a position to retain the edgesof the stack of paper 78. The rear of the stack is located in place byan indexing bar 102 which is mounted by means of a bracket 104 to across bar 106 which extends from frame member 10 to frame member 12.These indexing bars are examplary only and many other forms of supportsand guides may be substituted therefore. In the preferred embodiment theessential invention resides in the use of a grooved feed drum and aseparator plate as shown to insure a positive but gentle separation ofthe pieces of paper from the feed drum. In addition, the combinationtherewith of the adjustable stack supporting plate 70 and the air jet 98provides additional assurance that one piece of paper at a time isselected by the feed drum. The combination of these features permitsextremely light pieces of paper to be fed from stack 78 with reliableindividual selection and accurate registration. The vacuum source 52 maybe connected to the interior of the feed drum 25 through a valved line.However, as the suction holes are open to atmosphere once the paperpasses on to the separator plate, the vacuum within the drum is lostuntil the suction holes are again closed by the next piece of paper.

Since the preferred embodiment is shown only schematically in thedrawings it is obvious that a number of variations can be made withoutdeparting from the spirit and scope of the invention. Hence, thefollowing claims are presented with the intention of describing thepatentable improvements herein contemplated.

Iclaim:

1. A printing press feeding means comprising in combination:

a feed drum having a generally cylindrical portion with a plurality ofcircumferential grooves on said cylindrical portion, said cylindricalportion having at least one hole therein connected to a vacuum source soas to adapt said drum to grasp pieces of stock by suction;

means connected to said feed drum adapted to rotationally oscillate saidfeed drum;

a separation plate abutting said drum, said separation-plate having aplurality of projections extending from the abutting edge of said plateand into said circumferential grooves, the oscillation of said feed drumbeing long enough to carry the vacuum holes periodically under saidseparation plate;

a stack supporting member, adjustable in height, positioned to hold astack of stock with the edges of the stock at a predetennined heightabove said drum; and

air jet means just above said feed drum positioned to direct a jet ofair at the edges of the stock near the drum so as to help separate themfor easier grasping by said feed drum.

2. The apparatus of claim 1 in which said supporting member is pivotallysupported on a frame which frame also supports said feed drum, saidmeans connected to said drum, said separation plate, and said air jetmeans.

3. The apparatus of claim 2 in which said supporting member isadjustable in height by means of at least one threaded adjusting bolt onsaid frame positioned to engage the underside of said supporting member.

4. The apparatus of claim 3 in which said grooves have a generallyrectangular cross section.

5. The apparatus of claim 4 in which said plurality of projections onsaid separation plate are generally rectangular so as to be co rlfiruent to said grooves.

6. e apparatus of claim 5 in which the drum contacting portions of saidplurality of projections are beveled to a shape approximating the bottomof said grooves.

7. The apparatus of claim 6 in which there are a plurality of holes insaid feed drum connected to a vacuum source, said holes being positionedin the cylindrical portion of said feed drum between said grooves.

1. A printing press feeding means comprising in combination: a feed drumhaving a generally cylindrical portion with a plurality ofcircumferential grooves on said cylindrical portion, said cylindricalportion having at least one hole therein connected to a vacuum source soas to adapt said drum to grasp pieces of stock by suction; meansconnected to said feed drum adapted to rotationalLy oscillate said feeddrum; a separation plate abutting said drum, said separation platehaving a plurality of projections extending from the abutting edge ofsaid plate and into said circumferential grooves, the oscillation ofsaid feed drum being long enough to carry the vacuum holes periodicallyunder said separation plate; a stack supporting member, adjustable inheight, positioned to hold a stack of stock with the edges of the stockat a predetermined height above said drum; and air jet means just abovesaid feed drum positioned to direct a jet of air at the edges of thestock near the drum so as to help separate them for easier grasping bysaid feed drum.
 2. The apparatus of claim 1 in which said supportingmember is pivotally supported on a frame which frame also supports saidfeed drum, said means connected to said drum, said separation plate, andsaid air jet means.
 3. The apparatus of claim 2 in which said supportingmember is adjustable in height by means of at least one threadedadjusting bolt on said frame positioned to engage the underside of saidsupporting member.
 4. The apparatus of claim 3 in which said grooveshave a generally rectangular cross section.
 5. The apparatus of claim 4in which said plurality of projections on said separation plate aregenerally rectangular so as to be congruent to said grooves.
 6. Theapparatus of claim 5 in which the drum contacting portions of saidplurality of projections are beveled to a shape approximating the bottomof said grooves.
 7. The apparatus of claim 6 in which there are aplurality of holes in said feed drum connected to a vacuum source, saidholes being positioned in the cylindrical portion of said feed drumbetween said grooves.